Last week, my ageing motorcar started making an odd noise. The service manager told me I needed a replacement camfleugal pin. He gave me a list of 10 suppliers. Which one did I want them to use? I don't know much about camfleugal pins. I told him to get it from where he normally gets them.

The illusion of choice is important. Patients who need to go to hospital are now offered a "choice" under the government's much publicised "Choose and Book" (CAB) system. But how does CAB work in reality?

Mary has a cartilage problem in her right knee. It's been niggling away for a year or so. Hardly urgent, but she needs an MRI scan and an orthopaedic surgeon. I suggested she should see Mr Brown, our excellent local consultant, but Mary wanted to "choose and book". So, instead of a personal referral to Mr Brown, I wrote a "Dear Comrade" referral letter to the CAB Commissar.

A week later, Mary was back in high dudgeon. She had narrowed her "choice" down to two appointments; one in two weeks' time with Mr Smooth, an orthopaedic consultant 12 miles away, and one in eight weeks' time with Mr Brown.

Unlike Mary, I am an educated consumer of secondary medical care. I do not refer patients to Mr Smooth for reasons that explain why he does not have a long waiting list. Mary does not know that, and I cannot tell her. Fortunately, she does not want to travel 12 miles to see Mr Smooth. "But why should I have to wait eight weeks? That is outrageous."

Mr Brown is struggling to hit government targets. Five years ago his waiting list was 14 weeks. Yes, it is now eight weeks but only because box-ticking commissars have commandeered the two beds that used to be reserved for emergencies. Those beds are now permanently occupied by people such as Mary, all having non-urgent surgery. Box ticked. Target hit. Foundation status hospital. But what happens when there is a multiple pile-up on the M1, no acute beds and a log-jam of patients stacked up in casualty? The CAB commissar? Nowhere to be found. We have paid a high price to get waiting lists down, a price measured by our inability to cope promptly with emergencies.

And Mary? She is still angry. The government promised her the healthcare she wants, where she wants it and when she wants it and so, as she sees it, the NHS has failed to deliver.

• Dr Crippen is the pseudonym for a long-serving GP. Every week he will bring us a first-hand account of what's really happening in the NHS.